Yeah it's a dilemma for me being an avid bird person plus cats.Maybe that's safe, but even then some of these so-called "green" companies donate to other big organizations such as The Nature Conservancy that harm cats and are determined to harm them out of existence. The Sierra Club is another org that purports to be good but condones hunting, for instance. Smithsonian? Like The Nature Conservancy. ASPCA and HSUS? Pay their heads enormous salaries while in fact doing very little to help animals. The "free" T-shirts for $19 a month may make the gullible public feel smug and happy, but they're a useless prize for funding those huge salaries. Do your research, people. If you care.
Maybe climate change and humans taking over habitat are more of a threat to birds than cats. But I wish more people would keep cats indoors for the birds and for the cats sake.